Absorbent articles such as diapers, adult incontinence garments, feminine care products, child training pants, pull-ups, bandages, gloves and similar products that directly contact skin are well known. A disposable absorbent article is typically composed of a top layer that is adjacent to a user's body and a back layer that faces the clothing of the user. An absorbent material is located between the top layer and the bottom layer. The top layer permits a liquid from the user to move through the top layer toward the back layer. The back layer does not allow liquid to be transferred from the inside of the absorbent article onto the user's clothing. The absorbent material absorbs the liquid and keeps the skin dry.
During normal operation after a fluid is discharged from a user, the fluid will flow through the top layer and be absorbed by the absorbent material. The absorbent material is designed to absorb, redistribute, and store the fluid until the absorbent article is discarded. In some instances, however, fluid may return from the absorbent material to once again contact the user's skin. Fluid return would occur, for example, if the absorbent material was insufficiently composed to absorb the fluid. Unabsorbed fluid undesirably results in over-hydration of the contacted skin and in turn, increases a chance of skin irritation to the user. In addition to being an irritant, excessive moisture on the user's skin can cause, among other things, the growth of microorganisms that can lead to the onset of rashes or infection.
Various tests exist for measuring performance and suitability of absorbent materials to prevent the foregoing problems. Known tests include capacitance, conductance, electrical impedance, gravimetric, and/or evaporative or Trans-Epidermal Water Loss (TEWL) evaluations. Typically, these tests measure fluid absorbency, fluid leakage, and other criteria of the materials for use in absorbent articles.
One such test is the Adult Forearm Test or “armband” test, which is conventionally used to evaluate the effectiveness of disposable diapers to keep the skin dry. A variation of the armband test uses pre-loaded patches from diapers placed on an adult volar forearm. Changes in skin surface hydration are measured by evaporimetry or TEWL evaluation. Differences in skin surface hydration between cloth diapers and disposable paper diapers have been noted using this armband test variant.
Another armband test uses an intact diaper wrapped around the forearm. Physiological saline is injected into the diaper at a rate and volume that represent normal urination by a child. Post-occlusion measurements are made after one hour, and measurements of skin hydration are made by computerized evaporimetry or by electrical conductance.